Three-dimensional reconstruction method and system based on laser-multi-surface reflection rotating mirror, and medium

Abstract

The embodiment of the invention discloses a three-dimensional reconstruction method and system based on a laser-multi-surface reflection rotating mirror, and a medium. The method comprises the following steps: collecting line laser; the deviation angle of the line laser is changed by synchronously controlling the laser power and the rotation angle of the multi-surface reflecting rotating mirror, and a multi-mode laser coding pattern is output; determining a signal compensation amount according to a non-linear relationship between the space coordinates of the imaging end and the deviation angle of the line laser and a coordinate relationship between the initial reflecting surface and the rotating reflecting surface; compensating the multi-mode laser coding image according to the signal compensation amount, and outputting a target multi-mode laser coding image; and reconstructing a three-dimensional coordinate according to the target multi-mode laser coding pattern. The signal compensation amount is accurately determined through the non-linear relation between the space coordinates of the imaging end and the deviation angle of the line laser and the coordinate relation between the initial reflecting surface and the rotating reflecting surface, and the measurement deviation caused by system errors or environmental factors is eliminated.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional sensing measurement technology, and in particular to a three-dimensional reconstruction method, system and medium based on laser-polyhedral reflection rotating mirror. Background Art

[0002] At present, most structured light 3D sensors are based on DLP projection (Digital Light Processing), which can achieve better results for precision measurement in an ideal working environment. However, in complex application scenarios with a large field of view, such as sorting, welding, and gluing of industrial robots, the brightness of DLP is difficult to cope with, thus affecting the three-dimensional measurement results. Complex scenes include strong ambient light interference, and the presence of complex materials such as black and highly reflective on the surface of the scanned object. Therefore, it is necessary to develop a structured light three-dimensional sensing measurement technology using laser as the light source.

[0003] In the existing technology, the sensing technology mainly includes laser + MEMS (Micro-Electro-Mechanical System) sensing technology and laser + mechanical galvanometer sensing technology. Among them, the laser + MEMS laser technology has the advantages of small size and low cost, but the laser intensity is low and the accuracy is poor; the laser + mechanical galvanometer sensing technology can improve the laser intensity and further improve the accuracy compared to MEMS, but it is limited by the speed of the mechanical galvanometer, resulting in a low scanning speed of this sensing technology. Therefore, we proposed a laser + high-speed reflector sensing technology to break through the limitation of the galvanometer scanning speed; at the same time, we proposed a multi-modal three-dimensional scanning technology to further improve the measurement accuracy, enhance the measurement robustness and universality. Summary of the invention

[0004] Based on this, it is necessary to address the above problems and propose a three-dimensional reconstruction method, system and medium based on laser-polyhedral reflective rotating mirror. A three-dimensional reconstruction method based on laser-polyhedral reflective rotating mirror, the method comprising:

[0005] Collect line laser.

[0006] The offset angle of the line laser is changed by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, and a multi-modal laser coding pattern is output.

[0007] The signal compensation amount is determined according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface.

[0008] The multimodal laser coded image is compensated according to the signal compensation amount, and a target multimodal laser coded image is output.

[0009] The three-dimensional coordinates are reconstructed according to the target multi-modal laser coding pattern.

[0010] The signal compensation amount is determined according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface, specifically including:

[0011] The nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser is determined.

[0012] The expression of the multi-modal laser coding pattern output by the imaging end is determined according to the nonlinear relationship.

[0013] The input end signal compensation expression is determined according to the relationship between the multi-modal laser coding pattern expression and the imaging end target output.

[0014] Determine the coordinate relationship between the initial reflection surface and the rotating reflection surface.

[0015] Based on the coordinate relationship between the initial reflection surface and the rotation reflection surface, the rotation reflection surface coordinate model is determined according to the input end signal compensation expression.

[0016] The spatial offset is determined according to the rotating reflection surface coordinate model.

[0017] Based on the nonlinear relationship, the line laser offset is determined according to the spatial offset.

[0018] The line laser offset is substituted into the input end signal compensation expression to determine the signal compensation amount.

[0019] Wherein, the input end signal compensation expression is determined according to the relationship between the multi-modal laser coding pattern expression and the imaging end target output, specifically including:

[0020] according to

[0021]

[0022] Determine the input signal compensation expression, where, is the signal compensation amount, f1(·) is the target output at the imaging end, f2(·) is the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser, w is the rotation speed of the rotating mirror, and θ is the rotation angle of the rotating mirror.

[0023] The linear laser offset is substituted into the input end signal compensation expression to determine the signal compensation amount, which specifically includes:

[0024] The signal compensation amount is based on Determine, among which, is the signal compensation amount, f1(·) is the target output at the imaging end, θ is the mirror angle, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, d is the vertical distance from the laser light source to the center of the reflection mirror, and D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface.

[0025] Wherein, reconstructing the three-dimensional coordinates according to the target multimodal laser coding pattern specifically includes:

[0026] The target multi-modal laser encoding pattern includes a single line of laser light.

[0027] An image processing algorithm is used to extract the center of the light strip of the single-line laser, and to determine the sub-pixel precision coordinates of the single-line laser in an image coordinate system.

[0028] The sub-pixel precision coordinates are converted to an image plane in a camera coordinate system using camera intrinsic parameters.

[0029] For any image point on the image plane, a ray from the origin of the image plane to the image point is determined.

[0030] The three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection point of the ray and the single-line laser light plane.

[0031] Wherein, reconstructing the three-dimensional coordinates according to the target multimodal laser coding pattern specifically includes:

[0032] The target multi-modal laser coding pattern includes multi-line laser and Gray code.

[0033] The multi-line laser is encoded by using the Gray code to determine the light plane parameters of the multi-line laser.

[0034] The light plane equation of the multi-line laser is determined according to the light plane parameters of the multi-line laser.

[0035] An image processing algorithm is used to extract the center of each line of laser light in the multi-line laser, and to determine the sub-pixel precision coordinates of the multi-line laser in an image coordinate system.

[0036] The sub-pixel precision coordinates are converted to an image plane in a camera coordinate system using camera intrinsic parameters.

[0037] For any image point on the image plane, a ray from the origin of the image plane to the image point is determined.

[0038] The three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection point of the ray of the image point and the light plane equation of the corresponding line laser.

[0039] Wherein, reconstructing the three-dimensional coordinates according to the target multimodal laser coding pattern specifically includes:

[0040] The target multi-modal laser coding pattern includes a unidirectional phase-shift fringe pattern sequence and a Gray code.

[0041] A phase-map three-dimensional lookup table is obtained during calibration.

[0042] The folding phase is solved for the phase-shift fringe pattern sequence using an N-step phase shift method, and then the Gray code is used for decoding to determine the order of the folding phase and obtain the absolute phase.

[0043] The mapping coefficient corresponding to each image point is queried from the phase-mapping three-dimensional lookup table.

[0044] The reconstructed three-dimensional coordinates of each image point are determined according to the absolute phase and the mapping coefficient.

[0045] The step of determining the reconstructed three-dimensional coordinates of each image point according to the absolute phase and the mapping coefficient specifically includes:

[0046] according to Determine the X-axis coordinate of the reconstructed 3D coordinates of each image point, where X c is the X-axis coordinate, N is the polynomial order, n is a certain order, a n is the polynomial mapping coefficient of the X-axis, For phase.

[0047] according to Determine the Y-axis coordinate of the reconstructed 3D coordinates of each image point, where Y c is the Y-axis coordinate, b n is the polynomial mapping coefficient of the Y axis, N is the polynomial order, n is a certain order, For phase.

[0048] according to The Z-axis coordinate of the reconstructed 3D coordinates of each image point, where Z c is the Z-axis coordinate, c n is the polynomial mapping coefficient of the Z axis, N is the polynomial order, n is a certain order, For phase.

[0049] A three-dimensional reconstruction system based on laser-polyhedral reflective rotating mirror, the system comprising:

[0050] Line laser acquisition module, used to acquire line laser.

[0051] The multi-modal laser coding pattern output module is used to change the offset angle of the line laser by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, and output a multi-modal laser coding pattern.

[0052] The signal compensation amount determination module is used to determine the signal compensation amount according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface.

[0053] The target multimodal laser coded image output module is used to compensate the multimodal laser coded image according to the signal compensation amount and output the target multimodal laser coded image.

[0054] The three-dimensional coordinate reconstruction module is used to reconstruct the three-dimensional coordinates according to the target multi-modal laser coding pattern.

[0055] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is caused to execute the steps of the method described above.

[0056] The embodiments of the present invention have the following beneficial effects:

[0057] By synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, the offset angle of the line laser can be flexibly adjusted to generate different laser coding patterns to meet different measurement requirements. In addition, the continuous rotation of the multi-faceted reflective mirror can quickly generate multiple scanning lines, improve the efficiency and speed of data acquisition, and the generated multi-modal laser coding pattern contains rich multi-dimensional information, which helps to reconstruct the three-dimensional coordinates more accurately. Furthermore, by considering the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface, the signal compensation amount can be accurately calculated to eliminate the measurement deviation caused by system error or environmental factors, and the multi-modal laser coding image is compensated according to the signal compensation amount, and the target multi-modal laser coding image is output. Furthermore, by processing the target multi-modal laser coding pattern, accurate three-dimensional coordinate data can be generated to achieve three-dimensional visualization of the measured object, improve measurement accuracy, and enhance measurement robustness and universality. The reconstructed three-dimensional coordinate data can be used in many fields, such as industrial automation, robot navigation, three-dimensional printing, medical imaging, etc., and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0059] in:

[0060] Figure 1A schematic flow chart of an embodiment of a three-dimensional reconstruction method based on laser-polyhedral rotating mirror provided by the present invention;

[0061] Figure 2 A schematic structural diagram of an embodiment of a laser-polygonal reflective mirror module provided by the present invention;

[0062] Figure 3 A schematic diagram of an embodiment of laser reflection by a multi-faceted reflective rotating mirror provided by the present invention;

[0063] Figure 4 A schematic diagram of another embodiment of laser reflection by the multi-faceted reflective rotating mirror provided by the present invention;

[0064] Figure 5 A plane rectangular coordinate diagram of an embodiment of a four-sided reflective rotating mirror provided by the present invention located in a plane rectangular coordinate system;

[0065] Figure 6 A schematic flow chart of another embodiment of the three-dimensional reconstruction method based on laser-polyhedral reflecting mirror provided by the present invention;

[0066] Figure 7 A schematic diagram of an embodiment of a multi-modal laser coding pattern offset before compensation provided by the present invention;

[0067] Figure 8 A schematic diagram of an embodiment of the planar light intensity spatial distribution of the target multi-modal laser coding pattern before and after compensation provided by the present invention;

[0068] Fig. 9 A schematic diagram of another embodiment of the multi-modal laser coding pattern offset before compensation provided by the present invention;

[0069] Fig.10 A schematic diagram of another embodiment of the planar light intensity spatial distribution of the target multi-modal laser coding pattern before and after compensation provided by the present invention;

[0070] Fig.11 A schematic structural diagram of an embodiment of a three-dimensional reconstruction system based on a laser-polygonal reflecting mirror provided by the present invention;

[0071] Fig.12 A schematic structural diagram of a storage medium according to an embodiment of the present invention. DETAILED DESCRIPTION

[0072] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] like Figure 1 As shown, Figure 1 A schematic diagram of a flow chart of an embodiment of a three-dimensional reconstruction method based on a laser-polygonal reflective rotating mirror provided by the present invention. A three-dimensional reconstruction method based on a laser-polygonal reflective rotating mirror, the method comprising:

[0074] S101: Collect line laser.

[0075] For example, referring to Figure 2 , Figure 2 The schematic diagram of the structure of an embodiment of the laser-polyhedral reflective mirror module provided by the present invention, the laser-polyhedral reflective mirror is composed of a laser emitter 1 (blue light, wavelength 450nm), a linear laser beam expansion lens group 2, a polyhedral reflective mirror 3 and a control circuit 4. Among them, the linear laser beam expansion lens group 2 includes a Powell prism. The laser emitter 1 emits a point laser, which is expanded by a Powell prism and projected onto the polyhedral reflective mirror 3. The polyhedral reflective mirror 3 includes a mirror motor 31. The mirror motor 31 deflects at high speed according to the input timing analog voltage signal, and quickly reflects the line laser into the scene to form a coded pattern. By accurately controlling the input signal waveforms of the laser emitter 1 and the polyhedral reflective mirror 3 through the control circuit 4, the projection of different coded patterns can be realized. For each coded pattern, the control circuit 4 synchronously triggers the camera to collect images, thereby realizing multi-modal high-speed synchronous projection and collection integration.

[0076] S102: The offset angle of the line laser is changed by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror to output a multi-modal laser coding pattern.

[0077] For example, the present invention designs a multi-faceted reflective mirror 3 with N-sided coatings and reflective properties, and the mirror motor 31 rotates 360 degrees during operation, thereby avoiding the reciprocating vibration of the multi-faceted reflective mirror 3, scanning N times per cycle, and increasing the scanning speed by N times compared to the original. Figure 3 and Figure 4 As shown, Figure 3 This is a schematic diagram of an embodiment of laser reflection by a multi-faceted reflective rotating mirror provided by the present invention. Figure 4A schematic diagram of another embodiment of the multi-faceted reflective rotating mirror provided by the present invention for laser reflection. The multi-faceted reflective rotating mirror 3 includes four-faceted reflective rotating mirrors, the laser emitter 1 and the rotating axis of the multi-faceted reflective rotating mirror 3 are at different horizontal positions, the multi-faceted reflective rotating mirror 3 rotates counterclockwise at a certain speed, the laser emitter 1 emits a line laser, which is reflected after passing through a certain surface of the multi-faceted reflective rotating mirror 3, and the outgoing light scans the surface to be measured as the reflector rotates, and the actual effective scanning range of the field of view angle FOV = 40° is achieved by synchronously controlling the laser power and the multi-faceted reflective rotating mirror 3. The rotating mirror motor 31 can realize 4 projections in one rotation. At present, the rated speed of a small hollow cup brushless motor can reach 15,000 rpm (unit: rpm) under the premise of meeting the torque, and the final projection frame rate can reach 1000 frames / second.

[0078] S103: Determine a signal compensation amount according to a nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and a coordinate relationship between the initial reflection surface and the rotating reflection surface.

[0079] For example, referring to Figure 5 , Figure 5 A plane rectangular coordinate diagram of an embodiment of the four-sided reflective rotating mirror provided by the present invention in a plane rectangular coordinate system. A plane rectangular coordinate system is established with the center point O of the four-sided reflective rotating mirror as the center of the circle. The initial angle of the four-sided reflective rotating mirror is 45° with the x and y axes, and the intercept is a as the initial reflection surface. The laser light source S emits a linear laser incident light y=d along the negative direction of the x-axis, which is incident on one point of the initial reflection surface. The reflected light of the line laser travels D along the positive direction of the y-axis and hits point P0 on the working surface;

[0080] Assume that the mirror angle θ is positive when it rotates counterclockwise, such as Figure 5 The four-sided reflective mirror rotates counterclockwise around the center of the reflective mirror point O at an angle θ to serve as a rotating reflective surface, and the intersection line laser incident light is at point R off At this time, the reflection point on the incident laser line has a δ=R on -R off The reflected light of the line laser moves along with the reflective mirror, and rotates twice the angle θ, intersecting the working surface at P off , over R on Make R off The parallel line of the work surface intersects the work surface at P on It can be seen that the light projected on the object plane also shifts by δ, which is called spatial offset error.

[0081] Furthermore, the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser is determined. First, assume that the target laser coding pattern outputted from the imaging end is I=f1(x). Taking the output cosine variation pattern as an example, when the cosine time series signal is inputted to the laser, that is, I in =costn , because the mirror angle is a function of time, denoted as θ = wt n , t n is the time series, w is the rotation speed of the mirror, then the line laser expression at the input end can be recorded as:

[0082]

[0083] Among them, I in is the input end line laser intensity, w is the rotating mirror speed, θ is the rotating mirror angle, f in is the input signal of the line laser, A is the background intensity, and B is the modulation depth.

[0084] Furthermore, it is easy to obtain the nonlinear relationship between the spatial coordinate x of the imaging end line laser and the rotation mirror angle θ, as shown in the following formula:

[0085]

[0086] Among them, x is the spatial coordinate of the line laser at the imaging end, θ is the mirror angle, δ is the line laser offset, is the horizontal coordinate of point P0 in space coordinates, P off The horizontal coordinate of the point in space coordinates, P on The horizontal coordinate of the point in the space coordinate system, D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface.

[0087] Obviously, x and θ are in a nonlinear relationship. The laser coding pattern formed at the imaging end by the cosine time series signal uniformly sampled at the input end will deviate from the cosine variation relationship and be deformed. This deviation is called nonlinear error.

[0088] in, is a constant, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, and d is the vertical distance from the laser light source to the center of the reflection mirror. For a multi-faceted reflection mirror, δ≠0, there are both nonlinear errors and spatial offset errors.

[0089] At this time, the expression of the multi-modal laser coding pattern output at the imaging end can be recorded as:

[0090]

[0091] Among them, I out is the light intensity of the multi-modal laser coding pattern at the input end, f in (·) is the input signal of the line laser, f2(·) is the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser, A is the background intensity, and B is the modulation degree.

[0092] Further, based on the multi-modal laser coding pattern expression, in order to make the multi-modal laser coding pattern outputted on the imaging surface be the imaging end target output I out =f1(x), then the input signal compensation expression is as follows:

[0093]

[0094] Furthermore, the coordinate relationship between the initial reflection surface and the rotating reflection surface is determined. When the reflection mirror rotates counterclockwise by an angle of θ, the old coordinates and the new coordinates satisfy:

[0095]

[0096] Among them, (x, y) is the old coordinate of the initial reflection surface, (x ′ ,y ′ ) is the new coordinate of the rotating reflection surface, and when θ = 0, the initial reflection surface is on x + y = a, that is, Wherein, a is the intercept of the initial reflection surface in the plane rectangular coordinate system.

[0097] Furthermore, the input signal compensation expression is substituted into the coordinate relationship between the initial reflection surface and the rotation reflection surface to obtain the rotation reflection surface coordinate model, which is as follows:

[0098]

[0099] Furthermore, the spatial offset is determined according to the rotating reflection surface coordinate model. Let the ordinate y in the rotating reflection surface coordinate model be ′ =d, determine the point As shown below:

[0100]

[0101] Where d is the vertical distance from the laser light source to the center of the reflective mirror, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, P off The horizontal coordinate of the point in space coordinates, θ is the angle of the mirror.

[0102] Therefore, combined with Figure 3 , the spatial offset δ is shown in the following formula:

[0103]

[0104] Where δ is the line laser offset, θ is the mirror angle, For R off The horizontal coordinate of the point in space coordinates, For R onThe horizontal coordinate of the point in the spatial coordinate system, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, and d is the vertical distance from the laser light source to the center of the reflecting mirror.

[0105] Furthermore, the spatial offset is substituted into the nonlinear relationship to determine the line laser offset, which is shown in the following formula:

[0106]

[0107] in, is the horizontal coordinate of point P0 in space coordinates, P off The horizontal coordinate of the point in the spatial coordinate system, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, d is the vertical distance from the laser light source to the center of the reflecting mirror, D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface, and θ is the angle of the mirror.

[0108] Finally, the signal compensation amount can be obtained by substituting the line laser offset into the input signal compensation expression. The specific expression of the signal compensation amount is shown as follows:

[0109]

[0110] in, is the signal compensation amount, f1(·) is the target output at the imaging end, θ is the mirror angle, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, d is the vertical distance from the laser light source to the center of the reflection mirror, and D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface.

[0111] S104: Compensate the multimodal laser coded image according to the signal compensation amount, and output a target multimodal laser coded image.

[0112] Exemplarily, the multimodal laser coded image is compensated according to the signal compensation amount. At this time, the output of the imaging end is a preset target multimodal laser coded image. The target multimodal laser coded image is shown in the following formula:

[0113]

[0114] Where m is the number of fringes, x1 is the left boundary of the laser-polygonal mirror at the imaging end, x2 is the right boundary of the laser-polygonal mirror at the imaging end, and x n is the coordinate of the line laser on the imaging surface, A is the background intensity, and B is the modulation degree.

[0115] It should be noted that since the signal compensation amount is based on the result, it has a compensation effect on both the coaxial mechanical galvanometer and the multi-faceted reflecting rotating mirror. The difference is that for the coaxial mechanical galvanometer, f2 does not contain a spatial offset error, δ=0; for the multi-faceted reflecting rotating mirror, f2 contains a spatial offset error, δ≠0.

[0116] S105: Reconstruct three-dimensional coordinates according to the target multi-modal laser coding pattern.

[0117] Exemplarily, the laser-polyhedral reflective mirror module combines three measurement modes: line scanning of single-line laser, surface scanning of multi-line laser and Gray code, and surface scanning of phase-shift stripes and Gray code. Therefore, the target multimodal laser coding pattern includes single-line laser, multi-line laser and Gray code, and phase-shift stripe pattern sequence and Gray code.

[0118] Specifically, the laser-polygonal reflective mirror is controlled by the main control module to project a single-line laser, quickly scan the object, and the camera collects the modulated light on the surface of the object. The center of the laser line collected by the camera is extracted through the image processing algorithm, and its sub-pixel precision coordinates in the image coordinate system are determined. The sub-pixel precision coordinates on the single-line laser are converted to the image plane with a focal length of 1 in the camera coordinate system by the internal parameters obtained during camera calibration. For any image point in it, the image plane origin and the ray of the image point are used to represent it, and the spatial intersection of the ray and the single-line laser light plane is determined to reconstruct the three-dimensional coordinates of the image point.

[0119] The main control module controls the laser-polyhedral reflective mirror to project multi-line laser and Gray code target multimodal laser coding patterns in sequence to quickly scan objects. Since there are multiple laser lines in the same plane at the same time, Gray code is used to encode multiple laser lines, that is, each Gray code value corresponds to a line of laser, and the parameters of the multi-line laser light plane are determined by the Gray code value, thereby converting the reconstruction of the multi-line laser into a single-line laser reconstruction.

[0120] The main control module controls the laser-polyhedral reflective mirror to sequentially project a set of unidirectional phase-shifted fringe patterns and Gray code target multimodal laser coding patterns, quickly scan objects, and the camera synchronously collects images. During calibration, a phase-mapping three-dimensional lookup table is obtained, and the N-step phase shift method is used to solve the folded phase of the collected image. The order of the folded phase is then solved by Gray code to expand and obtain the absolute phase. The mapping coefficient corresponding to each image point is queried from the calibrated lookup table, and the phase and mapping coefficient are substituted into the three-dimensional point calculation formula to reconstruct the three-dimensional coordinates.

[0121] From the above description, it can be seen that the present invention can flexibly adjust the offset angle of the line laser by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, thereby generating different laser coding patterns to meet different measurement requirements. In addition, the continuous rotation of the multi-faceted reflective mirror can quickly generate multiple scanning lines, improve the efficiency and speed of data acquisition, and the generated multi-modal laser coding pattern contains rich multi-dimensional information, which helps to reconstruct the three-dimensional coordinates more accurately. Further, by considering the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface, the signal compensation amount can be accurately calculated, thereby eliminating the measurement deviation caused by system error or environmental factors, and the multi-modal laser coding image is compensated according to the signal compensation amount, and the target multi-modal laser coding image is output. Further, by processing the target multi-modal laser coding pattern, accurate three-dimensional coordinate data can be generated, the measurement accuracy is improved, and the measurement robustness and universality are enhanced. The three-dimensional visualization of the measured object is realized, and the reconstructed three-dimensional coordinate data can be used in multiple fields, such as industrial automation, robot navigation, three-dimensional printing, medical imaging, etc., and has broad application prospects.

[0122] like Figure 6 As shown, Figure 6 A schematic flow chart of another embodiment of a three-dimensional reconstruction method based on a laser-polygonal reflective rotating mirror provided by the present invention. A three-dimensional reconstruction method based on a laser-polygonal reflective rotating mirror, the method comprising:

[0123] S201: Collect line laser.

[0124] It should be noted that step S201 Figure 1 This has been discussed in detail in the implementation scenario shown and will not be repeated here.

[0125] S202: The offset angle of the line laser is changed by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror to output a multi-modal laser coding pattern.

[0126] For example, referring to Figure 7 , Figure 7 This is a schematic diagram of an embodiment of the multi-modal laser coding pattern deviation before compensation provided by the present invention. Through simulation modeling, the deformation of the multi-modal laser coding pattern at the imaging end caused by the off-axis deviation and nonlinear transformation of the four-sided reflective rotating mirror with a side length of 6mm is tested at a working distance of D=800mm and a field of view of 40°, where NE is the nonlinear error and SE is the spatial deviation error. Figure 7 It can be seen that the nonlinear error has a greater impact on the ideal cosine curve, while the spatial offset error has a smaller impact on the ideal cosine curve.

[0127] S203: Determine the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser.

[0128] For example, referring to Figure 5 , assuming that the target laser coding pattern outputted from the imaging end is I=f1(x), taking the output cosine variation pattern as an example, when the cosine time series signal is inputted to the laser, that is, Because the mirror angle is a function of time, it is recorded as θ = wt n , t n is the time series, w is the rotation speed of the mirror, then the line laser expression at the input end can be recorded as:

[0129]

[0130] Among them, I in is the input end line laser intensity, w is the rotating mirror speed, θ is the rotating mirror angle, f in is the input signal of the line laser, A is the background intensity, and B is the modulation depth.

[0131] Furthermore, it is easy to obtain the nonlinear relationship between the spatial coordinate x of the imaging end line laser and the offset angle θ of the line laser, as shown in the following formula:

[0132]

[0133] Among them, x is the spatial coordinate of the line laser at the imaging end, θ is the mirror angle, δ is the line laser offset, is the horizontal coordinate of point P0 in space coordinates, P off The horizontal coordinate of the point in space coordinates, P on The horizontal coordinate of the point in the space coordinate system, D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface.

[0134] S204: Determine the expression of the multi-modal laser coding pattern output by the imaging end according to the nonlinear relationship.

[0135] For example, the expression of the multi-modal laser coding pattern output at the imaging end can be expressed as:

[0136]

[0137] Among them, I out is the light intensity of the multi-modal laser coding pattern at the input end, f in (·) is the input signal of the line laser, f2(·) is the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser, A is the background intensity, and B is the modulation degree.

[0138] S205: Determine an input-end signal compensation expression according to a relationship between a multi-modal laser coding pattern expression and an imaging-end target output.

[0139] For example, based on the multi-modal laser coding pattern expression, in order to make the multi-modal laser coding pattern outputted on the imaging surface be the imaging end target output I out =f1(x), then the input signal compensation expression is as follows:

[0140]

[0141] S206: Determine the coordinate relationship between the initial reflection surface and the rotating reflection surface.

[0142] Exemplarily, when the reflective mirror rotates counterclockwise by an angle of θ, the old coordinates and the new coordinates satisfy:

[0143]

[0144] Among them, (x, y) is the old coordinate of the initial reflection surface, (x ′ ,y ′ ) is the new coordinate of the rotating reflection surface, and when θ = 0, the initial reflection surface is on x + y = a, that is, Wherein, a is the intercept of the initial reflection surface in the plane rectangular coordinate system.

[0145] S207: Based on the coordinate relationship between the initial reflection surface and the rotation reflection surface, a coordinate model of the rotation reflection surface is determined according to an input end signal compensation expression.

[0146] Exemplarily, the input end signal compensation expression is substituted into the coordinate relationship between the initial reflection surface and the rotation reflection surface to obtain the rotation reflection surface coordinate model, and the rotation reflection surface coordinate model is as follows:

[0147]

[0148] S208: Determine the spatial offset according to the rotating reflection surface coordinate model.

[0149] For example, let the ordinate y in the rotating reflection surface coordinate model ′ =d, determine the point As shown below:

[0150]

[0151] Where d is the vertical distance from the laser light source to the center of the reflective mirror, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, P off The horizontal coordinate of the point in space coordinates, θ is the angle of the mirror.

[0152] Therefore, combined with Figure 3 , the spatial offset δ is shown in the following formula:

[0153]

[0154] Where δ is the line laser offset, θ is the mirror angle, For R off The horizontal coordinate of the point in space coordinates, For R on The horizontal coordinate of the point in the spatial coordinate system, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, and d is the vertical distance from the laser light source to the center of the reflecting mirror.

[0155] S209: Based on the nonlinear relationship, determine the line laser offset according to the spatial offset.

[0156] Exemplarily, the spatial offset is substituted into the nonlinear relationship to determine the line laser offset, which is shown in the following formula:

[0157]

[0158] in, is the horizontal coordinate of point P0 in space coordinates, P off The horizontal coordinate of the point in the spatial coordinate system, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, d is the vertical distance from the laser light source to the center of the reflecting mirror, D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface, and θ is the angle of the mirror.

[0159] S210: Substitute the line laser offset into the input end signal compensation expression to determine the signal compensation amount.

[0160] For example, the signal compensation amount can be obtained by substituting the line laser offset into the input end signal compensation expression. The specific expression of the signal compensation amount is shown in the following formula:

[0161]

[0162] in, is the signal compensation amount, f1(·) is the target output at the imaging end, θ is the mirror angle, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, d is the vertical distance from the laser light source to the center of the reflection mirror, and D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface.

[0163] S211: Compensate the multimodal laser coded image according to the signal compensation amount, and output a target multimodal laser coded image.

[0164] For example, based on the compensation formula, the deformation of the laser-polygonal reflective mirror structure can be corrected. Taking a 4-sided reflector with a side length of 6 mm as an example, a simulation is performed at a working distance of 800 mm and a field of view of 40°. The compensation results are as follows: Figure 8 As shown, Figure 8 This is a schematic diagram of an embodiment of the planar light intensity spatial distribution of the target multi-modal laser coding pattern before and after compensation provided by the present invention. Figure 8 It can be seen that the curve of the target multi-modal laser coding pattern after compensation completely coincides with the ideal cosine curve.

[0165] It should be noted that the target multi-modal laser coding pattern proposed in the present invention can be a cosine, square wave or other function, which is not specifically limited here. Fig. 9 and Fig.10 As shown, Fig. 9 A schematic diagram of another embodiment of the multi-modal laser coding pattern offset before compensation provided by the present invention, Fig.10 It is a schematic diagram of another embodiment of the planar light intensity spatial distribution of the target multi-modal laser coding pattern before and after compensation provided by the present invention, Fig. 9 and Fig.10 The multimodal laser coding pattern in is a square wave distribution. When compensating, first determine the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser. Determine the expression of the multimodal laser coding pattern output by the imaging end based on the nonlinear relationship. Determine the input end signal compensation expression based on the relationship between the multimodal laser coding pattern expression and the target output of the imaging end. Determine the coordinate relationship between the initial reflection surface and the rotating reflection surface. Based on the coordinate relationship between the initial reflection surface and the rotating reflection surface, determine the rotating reflection surface coordinate model according to the input end signal compensation expression. Determine the spatial offset according to the rotating reflection surface coordinate model. Based on the nonlinear relationship, determine the line laser offset according to the spatial offset. Substitute the line laser offset into the input end signal compensation expression to determine the signal compensation. Further, compensate the multimodal laser coding image according to the signal compensation amount, and output the target multimodal laser coding image. The compensation result of the square wave distribution is as follows. Fig.10 As shown, the light intensity curve at the imaging end after compensation completely coincides with the ideal intensity curve.

[0166] When the working distance of the 4-sided reflective rotating mirror with a side length of 6 mm is D=800 mm and the field of view is 40°, the maximum and standard deviation of the spatial offset error SE and the nonlinear error NE on the final imaging grayscale are shown in Table 1. Table 1 is a table showing the influence of the spatial offset error and the nonlinear error on the final imaging grayscale:

[0167] Table 1 shows the influence of spatial offset error and nonlinear error on the final imaging grayscale

[0168]

[0169] S212: Reconstruct three-dimensional coordinates according to the target multi-modal laser coding pattern.

[0170] Exemplarily, the laser-polyhedral reflective mirror module combines three measurement modes: line scanning of single-line laser, surface scanning of multi-line laser and Gray code, and surface scanning of phase-shift stripes and Gray code. Therefore, the target multimodal laser coding pattern includes single-line laser, multi-line laser and Gray code, and phase-shift stripe pattern sequence and Gray code.

[0171] Specifically, the target multimodal laser coding pattern includes a single-line laser; an image processing algorithm is used to extract the center of the light strip of the single-line laser, and the sub-pixel precision coordinates of the single-line laser in the image coordinate system are determined; the camera intrinsic parameters are used to convert the sub-pixel precision coordinates to the image plane in the camera coordinate system; for any image point on the image plane, the ray from the origin of the image plane to the image point is determined; and the three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection of the ray and the single-line laser light plane.

[0172] The target multimodal laser coding pattern includes multi-line laser and Gray code; the multi-line laser is encoded by Gray code to determine the light plane parameters of the multi-line laser; the light plane equation of the multi-line laser is determined according to the light plane parameters of the multi-line laser; the light strip center of each line laser in the multi-line laser is extracted by image processing algorithm to determine the sub-pixel precision coordinates of the multi-line laser in the image coordinate system; the sub-pixel precision coordinates are converted to the image plane in the camera coordinate system by using camera intrinsic parameters; for any image point on the image plane, the ray from the origin of the image plane to the image point is determined; the three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection of the ray of the image point and the light plane equation of the corresponding line laser.

[0173] The target multimodal laser coding pattern includes a unidirectional phase-shift fringe pattern sequence and Gray code; a phase-mapping three-dimensional lookup table is obtained during calibration; the phase-shift fringe pattern sequence is solved using the N-step phase shift method, and then decoded using Gray code to determine the order of the folded phase and obtain the absolute phase; the mapping coefficient corresponding to each image point is queried from the phase-mapping three-dimensional lookup table; based on the absolute phase and mapping coefficient, the reconstructed three-dimensional coordinates of each image point are determined. The X-axis coordinate of the reconstructed three-dimensional coordinates of each image point is determined according to the following formula:

[0174]

[0175] Among them, X c is the X-axis coordinate, N is the polynomial order, n is a certain order, a n is the polynomial mapping coefficient of the X-axis, For phase.

[0176] The Y-axis coordinate of the reconstructed 3D coordinates of each image point is determined according to the following formula:

[0177]

[0178] Among them, Y cis the Y-axis coordinate, b n is the polynomial mapping coefficient of the Y axis, N is the polynomial order, n is a certain order, is the phase;

[0179] The Z-axis coordinate of the reconstructed 3D coordinates of each image point is determined according to the following formula:

[0180]

[0181] Among them, Z c is the Z-axis coordinate, c n is the polynomial mapping coefficient of the Z axis, N is the polynomial order, n is a certain order, For phase.

[0182] From the above description, it can be known that the present invention can accurately calculate the signal compensation amount by considering the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface, thereby eliminating the measurement deviation caused by system errors or environmental factors, and compensating the multimodal laser coded image according to the signal compensation amount, and outputting the target multimodal laser coded image. In addition, the determination of the signal compensation amount improves the accuracy of the measurement data and provides a reliable basis for subsequent three-dimensional reconstruction. In the process of three-dimensional reconstruction, for local reflective or black areas, surface scanning of line laser or surface scanning can be used for supplementary scanning to further improve the measurement accuracy.

[0183] like Fig.11 As shown, Fig.11 A schematic diagram of the structure of an embodiment of a three-dimensional reconstruction system based on a laser-polygonal reflective rotating mirror provided by the present invention. A three-dimensional reconstruction system 10 based on a laser-polygonal reflective rotating mirror comprises:

[0184] The line laser acquisition module 11 is used to acquire line laser.

[0185] The multi-modal laser coding pattern output module 12 is used to change the offset angle of the line laser by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, and output a multi-modal laser coding pattern.

[0186] The signal compensation amount determination module 13 is used to determine the signal compensation amount according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface.

[0187] The target multimodal laser coded image output module 14 is used to compensate the multimodal laser coded image according to the signal compensation amount and output the target multimodal laser coded image.

[0188] The three-dimensional coordinate reconstruction module 15 is used to reconstruct the three-dimensional coordinates according to the target multi-modal laser coding pattern.

[0189] Exemplarily, in the online laser acquisition module 11, the line laser is collected. Further, in the multimodal laser coding pattern output module 12, the offset angle of the line laser is changed by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, and the multimodal laser coding pattern is output. Further, in the signal compensation amount determination module 13, the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser is determined; the multimodal laser coding pattern expression output by the imaging end is determined according to the nonlinear relationship; the input end signal compensation expression is determined according to the relationship between the multimodal laser coding pattern expression and the target output of the imaging end; the coordinate relationship between the initial reflection surface and the rotating reflection surface is determined; based on the coordinate relationship between the initial reflection surface and the rotating reflection surface, the rotating reflection surface coordinate model is determined according to the input end signal compensation expression; the spatial offset is determined according to the rotating reflection surface coordinate model; based on the nonlinear relationship, the line laser offset is determined according to the spatial offset; the line laser offset is substituted into the input end signal compensation expression to determine the signal compensation amount. Further, in the target multimodal laser coding image output module 14, the multimodal laser coding image is compensated according to the signal compensation amount, and the target multimodal laser coding image is output. Finally, the three-dimensional coordinates are reconstructed in the three-dimensional coordinate reconstruction module 15. Specifically, the target multimodal laser coding pattern includes a single-line laser; an image processing algorithm is used to extract the center of the light strip of the single-line laser, and the sub-pixel precision coordinates of the single-line laser in the image coordinate system are determined; the camera intrinsic parameters are used to convert the sub-pixel precision coordinates to the image plane in the camera coordinate system; for any image point on the image plane, the ray from the origin of the image plane to the image point is determined; and the three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection of the ray and the single-line laser light plane.

[0190] The target multimodal laser coding pattern includes multi-line laser and Gray code; the multi-line laser is encoded by Gray code to determine the light plane parameters of the multi-line laser; the light plane equation of the multi-line laser is determined according to the light plane parameters of the multi-line laser; the light strip center of each line laser in the multi-line laser is extracted by image processing algorithm to determine the sub-pixel precision coordinates of the multi-line laser in the image coordinate system; the sub-pixel precision coordinates are converted to the image plane in the camera coordinate system by using camera intrinsic parameters; for any image point on the image plane, the ray from the origin of the image plane to the image point is determined; the three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection of the ray of the image point and the light plane equation of the corresponding line laser.

[0191] The target multimodal laser coding pattern includes a unidirectional phase-shift fringe pattern sequence and a Gray code; a phase-mapping three-dimensional lookup table is obtained during calibration; the phase-shift fringe pattern sequence is solved for the folded phase using an N-step phase shift method, and then the Gray code is used for decoding to determine the order of the folded phase and obtain the absolute phase; the mapping coefficient corresponding to each image point is queried from the phase-mapping three-dimensional lookup table; and the reconstructed three-dimensional coordinates of each image point are determined based on the absolute phase and the mapping coefficient.

[0192] like Fig.12 As shown, Fig.12 The storage medium 20 stores at least one computer program 21, which is executed by a processor to implement the following. Figure 1 and Figure 6 In one embodiment, the storage medium 30 may be a storage chip, a hard disk, a mobile hard disk, a USB flash drive, an optical disk, or other readable and writable storage tools, or a server, etc.

[0193] The above describes specific embodiments of the present specification, and other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily have to be performed in the specific order or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0194] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device, equipment, and non-volatile computer-readable storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0195] The apparatus, device, non-volatile computer-readable storage medium and method provided in the embodiments of this specification correspond to each other, and therefore, the apparatus, device, and non-volatile computer storage medium also have similar beneficial technical effects as the corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the corresponding apparatus, device, and non-volatile computer storage medium will not be repeated here.

[0196] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0197] For the convenience of description, the above device is described by being divided into various units according to their functions and described separately. Of course, when implementing this specification, the functions of each unit can be implemented in one or more software and / or hardware. It should be understood by those skilled in the art that this specification embodiment can be provided as a method, system, or computer program product. Therefore, this specification embodiment can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this specification embodiment can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0198] This specification is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of this specification. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0199] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0200] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0201] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0202] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0203] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0204] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0205] This specification may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. This specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0206] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0207] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A three-dimensional reconstruction method based on laser-polyhedral reflective mirror, characterized in that: The method comprises: Collect line laser; The offset angle of the line laser is changed by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror to output a multi-modal laser coding pattern; Determine the signal compensation amount according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface; Compensating the multimodal laser coded image according to the signal compensation amount, and outputting a target multimodal laser coded image; The three-dimensional coordinates are reconstructed according to the target multi-modal laser coding pattern.

2. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 1, characterized in that: The signal compensation amount is determined according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface, specifically including: Determining a nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser; Determine the expression of the multi-modal laser coding pattern output by the imaging end according to the nonlinear relationship; Determining an input end signal compensation expression according to a relationship between the multi-modal laser coding pattern expression and an imaging end target output; Determine the coordinate relationship between the initial reflection surface and the rotating reflection surface; Based on the coordinate relationship between the initial reflection surface and the rotation reflection surface, a rotation reflection surface coordinate model is determined according to the input end signal compensation expression; Determining a spatial offset according to the rotating reflection surface coordinate model; Based on the nonlinear relationship, determining the line laser offset according to the spatial offset; The line laser offset is substituted into the input end signal compensation expression to determine the signal compensation amount.

3. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 2, characterized in that: The step of determining the input end signal compensation expression according to the relationship between the multi-modal laser coding pattern expression and the imaging end target output specifically includes: according to Determine the input signal compensation expression, where, is the signal compensation amount, f1(·) is the target output at the imaging end, f2(·) is the nonlinear relationship between the spatial coordinates of the imaging end and the offset angle of the line laser, w is the rotation speed of the rotating mirror, θ is the mirror rotation angle.

4. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 3, characterized in that: Substituting the line laser offset into the input end signal compensation expression to determine the signal compensation amount specifically includes: The signal compensation amount is based on Determine, among which, is the signal compensation amount, f1(·) is the target output at the imaging end, θ is the mirror angle, a is the intercept of the initial reflection surface in the plane rectangular coordinate system, d is the vertical distance from the laser light source to the center of the reflection mirror, and D is the projection distance of the line laser moving along the positive direction of the longitudinal axis after being deflected by the initial reflection surface.

5. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 2, characterized in that: The reconstructing three-dimensional coordinates according to the target multi-modal laser coding pattern specifically includes: The target multi-modal laser coding pattern includes a single line of laser; An image processing algorithm is used to extract the center of the light strip of the single-line laser, and to determine the sub-pixel precision coordinates of the single-line laser in an image coordinate system; The sub-pixel precision coordinates are converted to an image plane in a camera coordinate system using camera intrinsic parameters; For any image point on the image plane, determine a ray from the origin of the image plane to the image point; The three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection point of the ray and the single-line laser light plane.

6. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 2, characterized in that: The reconstructing three-dimensional coordinates according to the target multi-modal laser coding pattern specifically includes: The target multi-modal laser coding pattern includes multi-line laser and Gray code; Encoding the multi-line laser using the Gray code to determine the light plane parameters of the multi-line laser; Determining a light plane equation of the multi-line laser according to the light plane parameters of the multi-line laser; An image processing algorithm is used to extract the center of each line of laser light in the multi-line laser, and to determine the sub-pixel precision coordinates of the multi-line laser in an image coordinate system; The sub-pixel precision coordinates are converted to an image plane in a camera coordinate system using camera intrinsic parameters; For any image point on the image plane, determine a ray from the origin of the image plane to the image point; The three-dimensional coordinates of the current image point are reconstructed by determining the spatial intersection point of the ray of the image point and the light plane equation of the corresponding line laser.

7. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 2, characterized in that: The reconstructing three-dimensional coordinates according to the target multi-modal laser coding pattern specifically includes: The target multi-modal laser coding pattern includes a unidirectional phase-shift fringe pattern sequence and a Gray code; A phase-mapping three-dimensional lookup table is obtained during calibration; Using an N-step phase shift method to solve the folded phase for the phase-shifted fringe pattern sequence, and then decoding it using the Gray code to determine the order of the folded phase and obtain the absolute phase; Querying a mapping coefficient corresponding to each image point from the phase-mapping three-dimensional lookup table; The reconstructed three-dimensional coordinates of each image point are determined according to the absolute phase and the mapping coefficient.

8. The three-dimensional reconstruction method based on laser-polygonal reflective rotating mirror according to claim 7, characterized in that: Determining the reconstructed three-dimensional coordinates of each image point according to the absolute phase and the mapping coefficient specifically includes: according to Determine the X-axis coordinate of the reconstructed 3D coordinates of each image point, where X C is the X-axis coordinate, N is the polynomial order, n is a certain order, a n is the polynomial mapping coefficient of the X-axis, is the phase; according to Determine the Y-axis coordinate of the reconstructed 3D coordinates of each image point, where Y c is the Y-axis coordinate, b n is the polynomial mapping coefficient of the Y axis, N is the polynomial order, n is a certain order, is the phase; according to The Z-axis coordinate of the reconstructed 3D coordinates of each image point, where Z c is the Z-axis coordinate, c n is the polynomial mapping coefficient of the Z axis, N is the polynomial order, n is a certain order, For phase.

9. A three-dimensional reconstruction system based on laser-polygonal reflective mirror, characterized in that: The system comprises: Line laser acquisition module, used to acquire line laser; A multi-modal laser coding pattern output module, used to change the offset angle of the line laser by synchronously controlling the laser power and the rotation angle of the multi-faceted reflective mirror, and output a multi-modal laser coding pattern; A signal compensation amount determination module, used to determine the signal compensation amount according to the nonlinear relationship between the imaging end space coordinates and the offset angle of the line laser and the coordinate relationship between the initial reflection surface and the rotating reflection surface; A target multimodal laser coded image output module, used for compensating the multimodal laser coded image according to the signal compensation amount, and outputting a target multimodal laser coded image; The three-dimensional coordinate reconstruction module is used to reconstruct the three-dimensional coordinates according to the target multi-modal laser coding pattern.

10. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 8.

Images